Studies On The Biocontrol Mechanism Of Actinomycetes Strain YB024 To Wheat Take-all

13 biocontrol strains were collected from different units, their inhibiting activity to Gaeumannomyces gramims var. tritici (G.g.t). was tested in vitro.by dual cultures. The result showed that they have given inhibiting activity to (G.g.t). In the 13 biocontrol strains, T4 have the highest inhibiting activity (63.41%), the inhibitory rate of S37, B22 and YB024 to G.g.t are60.37°/,59.15% and 53.17%.The control effects of 13 biocontrol strains to take-all. were tested in pots and in plots by seed trteatment. The result showed that YB024 has best control effect to take-all, the effect is 58.92% in pots and , in plots experiment the result showed that the wheat treated by actinomycetes srain YB024 have the lowest rate of white-head(27.9%), and the control effect of actinomycetes srain YB024 is also the highest(57.67%),the second one is B22, its average control effect is 52.59%.Futhermore, the effect of growth-promoting of 13 biocontrol strains on wheat growth and yield was tested. the result showed that the biocontrol strain S024 promote wheat seeding, G21-33 have a growth-promoting effect on wheat fresh weight and plant height.The biocontrol mechanism of YB024 was studied. The fermentation filtrate of YB024 has remarkable inhibiting activity to G. graminis var. tritici. Along with the dosage of filtrate increasing, the inhibiting activity is higher gradually. The result indicate that YB024 can produce antibiotics,which has inhibition effect to G. graminis var. tritici.The analysis results of rhizosphere microorganism flora showed that fungus and actinomycetes after treated by YB024 during the whole growing stage, the result indicate that, after treated by biocontrol agent YB024, the population of rhizosphere fungus and actinomyces are both higher than CK at seedling stage, but is both lower than CK at jointing stage and adult plant stage; The population of bacteria is always higher than CK during the whole growing stage. we also different teatment have great effect on the varieties and dominate species of Rhizosphere microorganism, the rhizosphere species number and superior for each treatment were different.The actinomycetes stain YB024 was tagged with Rifampicin, the tagged actinomycetes stain YB024 has resistant ability to 80ug.ml^-1 Rifampicin and its colonized...